Operating mechanism for timepieces



Dec. 1, 1925- 1,564,124

(5. H. COOPER OPERATING MECHANISM FOR TIMEPIECES Original Filed April 1922 Patented Dec. 1, i225.

UNIT

GEORGE E. COOPER, OF HARTFORD, CONNECTICUT, .ASSIGNOR, BY MIESNE ASSIGN- MENTS, T0 INEWTON D. HOLBRODK, 0F THOMASTON, CONNECTICUT.

OPERATING- IVIECHANISM FOR TIMEPIECES.

Application filed April 8, 1922, Serial No. 550,625. Renewed June 5, 1925.

To all whom it may concern:

Be it known that T, Gnonon H. Coornn, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented a new and useful Improvement in Operating Mechanism for Timepieces, of which the fol lowing is a specification.

This invention relates to mechanism which is designed for driving the time trains of watch and clock movements in which the source'of power is electrical.

The object of the invention is to provide a simple, cheap and compact mechanism which is actuated for tensioning the time train driving means byv periodic electricalimpulses controlled by the movement of the time train, the mechanism being so constructed and the connections so made that the driving force on the time train is not relaxed during the intervals at which the electrical impulses are made for tensioning the primary driving means, whereby the time train will be driven by a substantially uniform power and liability of stopping during such intervals will be eliminated.

In the embodiment of the invention illustratel this object is attained by arranging a field magnet and its armature in such manner as to tension a main motor spring when the magnet is energized and connecting the mechanism acted upon by the main spring with the time train by a supplemental motor spring that is tensioned by the main spring and keeps a continuous and practically even driving force on the time train.

In the accompanying drawings Figure 1 shows a back face view of a mechanism which embodies this invention. Fig. 2 shows a top edge view of this mechanism. Fig. 3 is a view looking at one side of the mechanism and showing its connection with a time train. Fig/l is a view looking at the other side of the mechanism. Fig. 5 is a fragmentary view of the mechanism showing the armature drawn down to the magnet as when the magnet is energized and the ar mature is renewing the tension of the main motor spring. Figs. 6 and 7 are detail views showing a form of the supplemental motor spring connection between the center arbor of the driving mechanism and center staff of the time train.

The invention is illustrated on enlarged scale as adapted to dr ve a watch movement,

the enclosing case being omitted and only so much of the movement being indicated as is necessary to show the connection of the operating mechanism to the time train.

A field magnet 1 is fastened to the back near one edge of a circular supporting plate 2. The armature 3 is pivotally mounted on a stud 4; projecting from the back of the plate near the opposite edge. The main motive spring in the form illustrated is a strip 5 of resilient metal. This spring is shownv as bent around the pivot stud with one end pressing against the armature and the other end engaged with a post 6, so as to swing the free end of the armature away from the magnet core. An arm 7 projects angularly from the armature beyond the pivot near the plate. This arm .may, as illustrated, be made integral with the armature and mounted on its end is a pawl 8. The pawl is held by a spring 9 in engagement with the teeth of a ratchet wheel 10, the arbor 11 of which projects through the supporting plate to the front. The oscillations of the armature and arm through the pawl impart intermittent rotatory movements to the ratchet wheel and its arbor. A detent 12 pivoted on' the back of the plate is held by a spring 13 engaged with theteeth of the ratchet wheel to prevent any backward movement of the wheel when the pawl is refinger 15 which is fastened on an insulating piece 16 that secured to the supporting plate. The main armature 3 opposite the magnet core has an opening 17 and the secondary armature 14 lies overthis opening. On the secondary armature is a hook 18 which is designed to engage with a finger 19 for limiting the movement of the secondary armature toward the magnet core. On the upper side near the free end of the main armature is a contact 20 and on the under side near the free end of the secondary armature is a contact 21.

vOne end 22 of the magnet winding leads to a battery or other source of electrical energy and the other end 23 of the magnet winding is connected with the spring finger which carries the secondary armature and is mounted on the insulating piece fastened to the plate. The main armature is ground ed on the plate and the other circuit wire armature is arrested by the engagement'of the hook 18 with the finger 19. The main armature continues its movement separating the contacts and opening the circuit through the magnet.

l Vhen the circuit is opened the secondary armature due to its resilience instantly returns to normal position while the main armature returns. to normal position for closing the circuit only as fast as the rotation of the ratchet wheel which is engaged by the pawl on the arm of the armature will permit. l l hen the main armature is returned to normal position the circuit is again closed through the contacts and the movements of the armatures is repeated. When the main armature swings-out under the influence of the main motor spring, the pawl imparts a rotatory movement to the ratchet wheel and as the main armature is drawn in the pawl is retracted to engage following teeth of the ratchet wheel. By providing the secondary spring armature the circuit is kept closed long enough to insure the drawing down of the main armature a sui'licient distance to cause the pawl to he passed from one tooth to the following tooth of the ratchet. The rotation oi the ratchet wheel under the impulses imparted by the oscillations of the main armature of course rotates the ratchet wheel arbor that extends through the supporting plate.

The time train may be that of an ordinary watch movement. The center staff 25 of the movement extends through the back plate 26. On this stad between the back plate and the front plate 27 is the usual gear 28 that is designed to be engaged by the escape train (not shown). Between the front plate and the-dial 29 is the usual train 30 for rotating the hour hand 31, the minute hand 32 fpeing rotated directly from the center sta Between the arbor 11 of the ratchet wheel of the driving mechanism and the center stall 25 of the time train, which are in axial alignment, is a yielding connection or secondary motor spring. In the drawings this spring is illustrated as comprising a flexible finger 33 projecting from the arbor and a flexible coil 34 projecting from the stafi. These two members are connected in such a manner that'the rotation of the arbor keeps a spring tension on the staii in the direction required to drive the time train. The form of this connec ing spring or secondary motor spring may be varied as desired.

With this simple mechanism the oscillawearer.

wheel in such manner that while the ratchet wheel is intermittently moved, there is alwaysa spring tension in driving direction between the ratchet wheel arbor and the center stai'l' ot' the time train. As a result of this there is always a spring driving force on the time train and this force being applied through the spring connection between the driving mechanism and the time train is practically constant. There is never any relaxation of the driving force on the time train, notwithstanding the fact that the oscillations or the main actuating armature under the electrical impulses are intermittent. The main driving motor winds up the secondary driving motor at very short intervals and a very slight amount at each interval but this is suiiicient to keep the power applied to the time train practically even. A watch or clock operated by this mechanism keeps very accurate time and there is no liability of its stopping when moved or subjected to jar. Such a clock or watch while useful for any service is particularly adapted for use on automobiles Where there is of course considerable jar and vibration.

The invention claimed is:

1. A time train driving mechanism com-- prising a supporting plate,.an electro-magnet mounted thereon, a pair of armatures adapted to be attracted toward the magnet, one armature having a longer movement than the other, contacts on said armatures adapted to be engaged during a portion oi the travel of the armatures toward the magnet, a spring for retracting thearmature having the longer movement, and means comprising a ratchet and pawl adapted to be advanced by the retraction of the armature under the influence of said spring.

2. A driving mechanism for a time piece comprising an electromagnet, a pair of armatures adapted to be attracted toward the magnet, one armature having a longer movement than the other, said armatures being normally in electrical contact but being separated when the armature having the longer movement is drawn away from the armature having the shorter movement, a spring tensioned by the movement of the armature having the longer movement, and a spring tensioned by the tension of said armature spring.

3. A driving mechanism for a time piece having a main driving spring, a secondary driving spring tensioned by the main drivmg spring, an electro-magnet, an armature actuated y the magnet for tensioning the 'main spring, and a secondary armature adapted to be electrically engaged by the mam armature for closing the circuit through the magnet, said secondary armature moving for a limited distance with the main armature for keeping the circuit closed an appreciable length of time.

4. A driving mechanism for a time piece having a main driving spring and a secondary driving spring, said latter spring being tensioned by the tension of the former spring, an electro-magnet, and a main armature and a secondary armature adapted to engage for closing the circuit through the magnet, the main armature having a longer travel than the secondary armature whereby the circuit is kept closed while the armatures spring being tensioned by the movement of the main armature.

5. A time train driving mechanism comprising a supporting plate, an electro-magnet mounted thereon, a pivotally mounted armature and a spring mounted armature adapted to be attracted toward the magnet, said pivotally mounted armature having a longer movementthan the spring mounted armature, contacts on said armatures adapted to be engaged during a portion of the travel of the armatures toward the magnet, a spring for retracting the pivoted armature, and means comprising a ratchet and pawl adapted to be advanced by the retraction of the pivoted armature.

GEORGE H. COOPER. 

